The Port of Seattle surveyed drayage truckers serving the port in 2006, 2008, and surveyed drivers again in 2013 in partnership with the University of Washington. This thesis describes the methodology used to survey drayage drivers at the Port of Seattle, describes the economic conditions of drayage drivers at the port and changes in economic conditions since previous surveys, and attempts to model driver earnings based on other driver characteristics.
By increasing the number of days that the survey was distributed, and by soliciting driver feedback to make the survey understandable and relevant to drivers, the 2013 survey was able to gather a larger survey size than previous efforts (290 responses in 2013, compared to 99 responses in 2008 and 167 responses in 2006).
From 2008 to 2013, there was a reduction in the number of drivers working five or more days per week, from 80% in 2008 to 70% in 2013. The percentage of drivers doing work other than port trucking has increased from 8% in 2008 to 37% in 2013. Findings suggest that due to changing conditions at the Port of Seattle, there is a growing population of drivers that do port trucking as a part-time job in combination with other forms of work, rather than a full-time occupation.
Attempts at modeling driver earnings based on other factors (English as a second language, trip type, doing work other than port trucking, and average hours worked per week) did not discover strong relationships between these factors and earnings. It is recommended that future efforts in this area use higher resolution earnings data than the data available from the 2013 survey.